Method of treating rubber and the like and the products obtained thereby



Patented Dec; 28, 1926.

UNITED STATES JAMES E. REEL; OF NEW YORK,

PATENT OFFICE.

I I ,1, assrenoamoxeanam nu safinoommmr, nawxonx, u. 71., a. concurrence-newness? Y m r m mmin an, mrm masvcr r Rom-airing.

This inventionrelates methods. of treat-c ing rubber and the likeland to the products obtained thereby, and has. for its principal object, to produce "by simple .and eflicient methods, grades-of rubber-or similarmaterial of higher degrees of-purity than have heretofore been produced. a .y There are several well-known the" rubber is producedin thenformtof a compact mass either'as sheets orzblocks. and

" 1s afterwards subjectedito awashing proc mess..- Aswan instance of this may. be omen-n stream of water while xthe rubber isbeing milled and thereafter dried; x

ble in-rfwater, whileothers'are insoluble in,

water .but' may be rendered soluble rby suite} 5 able treatment orlxdissolved out "by other suitable solvents. Instances:ofiwater insolu ble' non-rubber ingredients are protein and resin, the protein being madereadily:solublel by digestin g Withmproteolytic renzymes suchix aspapain or 'trypsin, and the 'resin being readily solublein acetone-' orzalcohoL' :J'It iSJ; not a known: that these non-rubber ingredients. have ever been. removed from; the crude-plas-22 tic rubberl-to such a degree of completeness;

as :to render: the rubber substantially pure.

The fact is-that: the no'n -rubber-V:constituents? aresrsozthoroughlyiimprisoned inhthe com-gs pactji mass forming the: crude rubber -sheet or? blocks :that it -is .jpractically"ximpossiblei tbs;

ua1'.-;5N.o 1,428,526: Hereithedatexis'gsprayed; r into; 0 .v w M i; heated. u'rrentwo1:aimorgzaother idrying-sme :aIihave found thatzif: th qdrytrubber, s in'z:

a suificiently :open or uncoinpacticonditionwitsz can besuccessfully subjected to a thorouglrtjl' reach istlienrv vWithsthe a solvents-:to seflect tliei removal to any-substantia degre of pe ,qfection-mie? washing treatment with :.water audit-O treatthenon-rubberil. eon'sti-tuents,-figradesmofi rubber; beingrthus'prodiicedf of farkgreate a.

I purity ithairhas-beenepossibl-td :attainhere v I "Qstateit is subjected ;to;)ca washingrtreatment':

with water; @This" mayzl-beiparriediout either p tofore. A a wMy invention iswnotvz'confined toany:

' 5 Application me -mm; 1e24qser11i m'; 721,811.;

of treating the rubber in asubstantially methods of preparing dry rubber fromx'latex wherein her :With; a: solvent ,foriremovingrthe; resin? from the latex provided. it is attainable a sufliciently open or uncompact'. condition for} successful treatment by thereagents and Y solvents employed. Broadly considered the I invention comprises the method 'orniethodsf open or uncompactv fornn withone or "more suitablexsolvents and a reagents'or ireagents when desired for removing non-rubber constituents therefrom 1 and flthesf production thereby I of a product or products '5, of farwfi i greater: purity from .a standpoint bf: thef elimination'of. such= constituents,: than has. been'lheretofore possible:to produce! .W h he abovejiintendedbreadth-10f in-1 vention' in view, the. invention thereforefcon templates 'f washing: the uncompact .v rubber: with water to remove the water-soluble non;

p i rubber"constituents;xior matin -therew- 20 Whenuthe latex is coagulated toxproducewi the rubber it containsw-variousf non-rubber? constituents, some of 'whicliare' readily solua proteolytici ven zymexfl-as for instance i-papainJ or'-.,trypsin or. treatingfthe, I10II-COmpaChIfllj-W80 presentafsuchlasacetoneszoralcoholg i or sub-- 7 eating the? nonec'oinpact; rubber to any Ilium er of thesestr'eatments, thereby producing a rubber ing; any? instance-S ofygreatertpurityf} thanthas heretofore been possible, ":1" sAsrbeforez stated; the; invention :gomprisesi I treating ii-ubbei:- i in: an rki'opena iore uncompact form; and) toxthis end t-the'sepi'eferred ema l" bodilrrentmthe .tr'eatinent supplied to 'crudew rubber produced; from atexaapreparedwbyfi; v whatkis known.:aszthe'ififsprayafmethodxli 'i-Ali? apparatus suitable fori,sosqiproducingi rubber e 1s:showifincthe patenqytot Gi'iiblriBradleygiet hambferz; rovidedi with a1 suitable; 95.

ticlesfias:stlieytefalli" toifthe es floorisicolleot fintoi heinr. 10f ano ,,nyuncdmpactspongy-mass In the: carryingaiout ofiimyri-inventionithe mass ofdryzrubbertinz'its uncompaets'pongyz 'in thechambe or ftergit' as been removed therefrom, but preferably by injecting sprays of water in the chamber below the 7 point where the latex has become dried.

mass.

- the water off that has acted upon the rubber as fresh water is added. By this process substantially all of the water-soluble nonrubber constituents, which usually comprise from -1013% of the entire mass, are re-.

moved. After drying the rubber a product is obtained far purer, as far as the removal of the water-soluble non-rubber constituents is concerned, than has heretofore been produced.

If it is desired to remove the protein, the spongelike mass or falling particles is subected to a suitable treatment which may be similar to that previously mentioned.

Likewise, if it is desired to remove-the resin constituent, the rubber is similarly treated with a suitable solvent such for instance as those already inentioned. I have obtained very. satisfactory results b treating the washed uncompact spongeli e rubber with a water'solutio'n of a proteolytic enzyme (for example papain 1 part to 100 parts of rubber), and after washing and preferably drying, again treating the uncompact. mass with .cold acetone after which it*- is dried. While the rubber may be subjected to only one of these treatments it will usually be desirable to subject it, for most uses, to all three treatments thereby securing a rubber of, the highest purity.

The treatments ma secutively and the ru ber washed between each treatment to remove the dissolved nonjectedtoadry rubber constituents, and their solvents as may be desired, the final product sub- .state is capable of being dried more per ectly than has been possible heretofore with the rubber inthe form of a compact sheet or block. The drying is performed also in less time, and at a lower temperature, thereby producing not only a purer rubber, but a lngher ads of rubber having high tensile strengt count of maintaining a greater portion of the'original nerve of the rubber than is possible where the higher tem eratures are employed necessary to dryy e rubber in slab or block form.

be performed con-.

mg process and it is des rable to dry the rubber after each treatment. The rubber in it's spon on ac- I claim and desire to A further advantage of washing rubber that has been formed by the spray method resides in the factthat the dry rubber so formed contains more water-soluble non- .rubber constituents than does rubbercoaguprior to the removal of the rubber, although of course the rubber may be removed from the chamber as a continuous operation. The rubber so washed is allowed to drain and the draining is preferably accelerated by carefully removing a great portion of the water in a centrifuge equipped with a basket similar to that used in laundries; It is then dried at a temperature of 100- 120 F, or lower in the spongelike form and c'anthus be dried to a moisture content of less than 2% moisture.-

In preparing rubber by the spray method the heated airor other gas used in coagulating the spray vpasses from the chamber carryin with it some of the dried rubber in the orm ofdu'stQ My invention may be availed of by passing the dustladen heated fluid through a second charmberyand subject -it to a spray of water which will carry the dried dust-like particles of latex with it to the floor of the receptacle and at the same time thoroughly wash the collected rubber particles thereby effecting both a saving and washing of the rubber carried by the heated medium. This washed rubber may be further treated if desired to remove the water-insoluble non-rubber constituents in a manner similar to that already described.

Materials which are ordinarily classed under the term rubber including balata, 'gutta percha, synthetic rubber, chicle, and the like, or mixtures of these, may be treated in a similar manner and products of similarly im r'oved characteristics obtained when desir and it is intended to include any such suitable substance or substances by the1 term rubber in the foregoing description an limited.

As many apparently widely different embodiments of this invention -ma'y be made without departing from the spirit thereof, it is to be-understood .that I do not intendto limit myself to the specific form of the in-.

vention as set forth except as indicated in the appended claims.

Having thus described my invention what t protect by Letters Paten 15:

1. method of purifying rubber which comprises sub'ectin latex to an atomizing treatment to orm '1 1 rubber in an uncom:

appended claims, otherwise pact plastic form and subjecting the rubber while in this form to treatments adapted to remove non-rubber constituents therefrom,-.

and recovering a purified rubber in an uncompact plastic form.

2. A method which comprises spraying latex to form dry rubber in an uncompact plastic form, and subjecting the dry rubber while in said uncompact plastic form to a washing treatment with water to remove the water-soluble non-rubber constituents.

3. A method which comprises spraying latex to form dry rubber in an uncompact plastic form, subjecting the rubber while in said uncompact form 'to a washing treatment with water to remove the water-soluble non-rubber constituents, and thereafter drying the rubber while in the uncompact form.

4. A method which comprises producing a spray of rubber particles and subjecting the particles while in the form of a spray to a liquid,

5. A method which comprises producing rubber in the form of a sprayof falling particles, subjecting the falling rubber particles to the action of a liquid, and subjecting the fallen particles collected in an uncompact mass to the action of a liquid.

6. A method which comprises treating latex to form a spray of dry rubber, collecting said dry rubber in an uncompacted spongy form, and subjecting said dry rub- .ber to the action of water and a reagent for rendering the protein soluble.

7. A method which comprises treating latex to'form a spray of dry rubber, collecting said dry rubber in an uncompacted spongy form,-and subjecting said dry rubber to the action of water and ai proteolytic enzyme for changing the insoluble proteins into a soluble form.

8. A method which comprises treating latex to form a spray of dry rubber, collecting said dry rubber in an uncompacted spongy form, and subjecting said dry rubber to the action of water and papain for changing the insoluble proteins into a soluble form. I X

9. A method of producing a pure rubber which comprises disposing latex into aspray of dry particles, collecting the particles in an uncompact spongy form and subjecting said uncompact spongy rubber to the action of solvents for the water insoluble non-rub ber constituents.

10. Transforming latex into a spray of dry particles, collecting said particles in an uncompact spongy form, and while in this form subjecting the rubber to a washing treatment with water to remove the watersoluble non-rubber constituents, and treating the uncompact mass to the action of solvents to remove the water insolublenon-rubber constituents.

11. A method for producing pure rubber which comprises atomizing latex into a dry ing atmosphere, collecting the dried particles in an uncompact spongy form, and subjecting the rubber while in said form to a Washing treatment with Water to remove the water-soluble non-rubber constituents, treating the uncompact mass to the action of water and a reagent for rendering the said protein soluble, and treating the uncompact mass to the action of a solvent for the resin.

12. Amethod for producing pure rubber which comprises atomizing latex into a drying atmosphere, collecting the dried particles in an uncompact spongy form, and subjecting the rubber While in said form to a washing treatment with water to'remove the water-soluble non-rubber constituents, treating the uncompact mass tothe action of water and papain for rendering the said protein soluble, and treating the, uncompact mass to the action of acetone for removing the resin. I

Signed at- New York city, in the county of New York, and State of New York, this 18th day of June, 1924.

JAMES H..REEL. 

